Tire inflation

[Barony]

I had a tire that was a little low, so I found the PSI on the side of the tire and filled to what was recommended on the side of the tire (44 psi). I then looked on the side of the frame on the truck and it recommended 35 psi, so I backed the tire down to that number. Two questions: 1) Why the difference between the tire mfg. and Ford?, and 2) Which number is right, 44 or 35 psi? Looking anywhere for mileage.

[Jeremy airjer W]

The rating on the tire is the maximum inflation for the maximum load the tire can carry. The heavier the load the more air you need in the tire to support it.

For normal driving use the manufacturers suggested inflation pressure. This will likely give you the best of the big three - traction, fuel economy, and braking.

There are all kinds of exceptions to this rule and more than likely you will probably read just about all of them before this thread fizzles. Go with the Manufacturers recommendation for everyday driving, add a couple of pounds when your loaded down and you should be just fine.

[Shack]

Airjer is right on the money!

For passenger cars, you can locate the factory tire specs in drivers door jam or I have found in pass rear door jam (Linc.). Look for grey or white decal/sticker.

On heavier trucks, tire pressure has an effect on load carrying capacity. Like Airjer stated bigger loads require higher tire pressure ( also load range of tire has a bearing in this as well).

Good luck!

[Fishook]

I have the same questions as Barony. Are you refering to the tire manufacture or the vehichle manufacture when you say "use the manufacturers suggested inflation pressure"? It wasn't clear to me which one I should follow. Just for the record, I use the pressure rating on the vehicle tag for my normal driving needs. Should I be using the psi as indicated on the tire?

[Shack]

Manufacturers in the above posts (I would assume) pertain to the vehicle, not the tire.

The decal in drivers door jam, rear door jam or trunk is in stalled by the factory that made that car, not the company that made the tire.

When you deal with this stuff all the time, you kind of get one sided to the "terms" thing. Good catch!

!!!!!The PSI rating on the tire is a "Max" rating only!!!!!!

Do not use this when set air pressure in the tires. Use the sticker located on vehicle that was installed from factory or consult dealer ship service department to get correct PSI for your vehicle, if you do not have a sticker.

[Whoaru99]

Use the pressures listed on the decal affixed to the vehicle.

Bear in mind though, if the tires have been changed to different size or load rating, the pressures listed on that OEM decal no longer are correct. The tire size and load information should be listed on that decal so you can verify whether or not it matches the tires that are actually on the vehicle.

[Fishook]

Thank you to both Whoaru99 and Shackbash for clearing this up. I appreciate it.